The cardinalfish wisely spend most of their time in their caves.
Their neighbor is a Mediterranean moray.
The eel is widely considered a fearsome hunter; so who on Earth, or in water, would dare approach it?
This tiny red shrimp appears to have a death wish.
The crustacean heads directly for the moray's mouth.
But this apparently merciless predator seems to welcome the visitor's attentions.
The cleaner shrimp performs an important task: removing parasites from the eel's skin.
In return, the shrimp receives food and board.
It is a profitable relationship for both sides, and others have taken note.
